Yield and Physiological Responses of Two Oat (Avena sativa L.) Cultivars to Varying Levels of Foliar Micronutrient Fertilization

Abstract

The low availability of micronutrients in alkaline soils represents one of the most critical limiting factors for oat (Avena sativa L.) productivity. A field experiment was conducted during the winter agricultural season of 2024–2025 in Al-Muthanna Governorate / Al-Khidhir District to evaluate the effects of three foliar application levels of chelated micronutrients (M0: distilled water, M1: intermediate level, and M2: high level of iron, zinc, and manganese) on the yield and physiological indicators of two oat cultivars (Al-Juda and Shifa). The experiment was designed using a randomized complete block design (RCBD) in a split-plot arrangement with three replications.

The results revealed a highly significant response  in both cultivars to the increased levels of micronutrient fertilization, with the highest yield component values recorded at the M2 level. The cultivar 'Shifa' significantly excelled under the influence of the high level (M2), achieving the highest number of panicles (410.7panicles m-2}, the highest number of grains per panicle (71.8grains, and the maximum 1000-grain weight (41.3g), compared to the minimum values recorded under the control treatment (M0) for the same cultivar, which were 295.0panicles m-2}, 48.6grains}, and 33.5 { g}, respectively. This morphological and physiological superiority was directly and positively reflected in the final yield. The interaction between the 'Shifa' cultivar and the M2 level achieved the highest economic grain yield 5.60 t ha-1 and biological yield (13.95t ha-1, significantly outperforming the 'Al-Juda' cultivar at the same fertilization level (4.85t ha-1 for grain yield and 12.80t ha-1 for biological yield), with a statistical difference exceeding the least significant difference value LSD 0.05} = 0.36t ha-1 for grain yield. Furthermore, the highest dry matter conversion efficiency (harvest index) was recorded under the same treatment (40.14%).

The study concludes that there is a highly significant genotype-by-environment (G \times E) interaction, reflecting the superior genetic plasticity of the 'Shifa' cultivar in utilizing elevated levels of foliar micronutrient nutrition and converting them into economic yield. The study recommends adopting the cultivation of the 'Shifa' cultivar integrated with the application of the high fertilization level (M2) as a sustainable agricultural recommendation package to achieve maximum productivity in the study area.